<script>
    $(document).ready(function () {
       $('.jui-button-set').buttonset();
    });
</script>
<div class="jui-button-set">
    {//$options|print_r}
    <volist name="options" id="option">
        <input type="radio" id="plain_selector_{$option.id}_{$key}" name="plain_selector"
               value="{$option.id}" <if condition="$option['selected']"> checked </if> >
        <label for="plain_selector_{$option.id}_{$key}">{$option.name}</label>
    </volist>
</div>